1. Field of the Invention
The present invention relates to an antenna device suitable for application to mobile terminal equipment such as mobile phones, PHS phones (PHS: Personal Handyphone System) and PDA equipment (PDA: Personal Digital Assistant) having communication functions, and relates to a mobile terminal apparatus equipped with such an antenna device. More particularly, the present invention relates to an antenna device having a widened frequency bandwidth and a multi-band construction, and to a mobile terminal apparatus equipped with such an antenna device.
2. Description of Related Art
Japanese Patent Application Publication (KOKAI) No. 2002-43826 (pages 3 to 4: FIG. 1) has heretofore disclosed a small-sized wide band antenna device which does not suffer a large fall in gain even when used in proximity to the human body. The antenna device has a rectangular full-wave loop antenna element installed in proximity to the base plate of a radio set, and the opposite ends of the loop antenna element are bent toward a feed point so as to produce a current distribution in which current becomes zero at the tip sections of the folded ends, and so as to concentrate current onto the loop antenna element. This construction reduces current components flowing on the base plate of the radio set, and suppresses the influence of the human body when the radio set is held by hand, as well as forms directivity characteristics corresponding to arrival waves.